Avro website is not up to date with release

[Jean-Baptiste Onofré]

Hi folks,

I just noted that the release mentioned on the website is still 1.11.1
(not 1.11.3), for documentation, blog, or download page.

If there are no objections, I will propose a PR to add 1.11.2 and
1.11.3 releases.

Regards
JB